RESUMO
PURPOSE: Transient global amnesia (TGA) is characterized by abrupt onset of antegrade amnesia usually seeking emergency care. We analyzed the clinical characteristics of TGA patients and the significance of diffusion weighted imaging (DWI) in the diagnosis of TGA. METHODS: Retrospective analysis was performed using electronic medical records of patients diagnosed as TGA in the emergency departments from January 2003 to December 2013. The patient's clinical characteristics and precipitants were analyzed, and detection rate of hippocampal lesion was compared according to the time to DWI after symptom onset (24 h). RESULTS: Of 372 consecutive TGA patients studied, 27 had a positive DWI lesion in hippocampus. Demographics and vascular risk profile were not significantly different between those in DWI (+) and DWI (-), and neither was duration of amnesia (p=0.076). However, the median time interval to DWI was significantly longer in DWI (+) than DWI (-) [7.5 (5.5~15.0) h vs. 6.0 (3.5~9.0) h, p=0.011]. In addition, the detection rate of hippocampal lesion increased with the time interval [0-6 h (4.1%), 6~12 h (10.7%), 12~24 h (11.1%), and >24 h (16.1%), p=0.004]. CONCLUSION: Positive hippocampal lesion on DWI can confirm the diagnosis of TGA; however, difference in lesion detectability in regard to time interval from symptom onset to DWI should be considered in diagnosis of TGA with DWI.